Instantiation of an abstract class via initializer list [duplicate]

Answer 1

This looks like a known g++ bug number 70939:

creating object of abstract class allowed in all versions of g++

g++ compiles ill formed C++ program successfully

class A {
public:
    A() {
        printf("A()\n");
    }
    virtual void b() const = 0;
};
int main() {
    const A& a{};
    a.b();
    return 0;
}

Your code does the same thing as this line

const A& a{}

as part of g({}) invocation.